Bifunctional high intensity discharge projector headlamp

Abstract

A projector headlamp utilizing only a single HID bulb for projecting light in a forward direction generally along a horizontal axis selectably between low beam and high beam conditions while shifting the hot spot as required between these conditions.

What is claimed is:  
     
       1. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located substantially at said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a condenser axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield, said reflector, and said condenser lens between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and substantially parallel to said horizontal axis, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and raised by an angle A with respect to said horizontal axis, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       2. A projector headlamp according to claim  1 , wherein 0°<A≦5°. 
     
     
       3. A projector headlamp according to claim  1 , wherein 1°≦A≦3°. 
     
     
       4. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located substantially at said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a condenser axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield and said condenser lens between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and substantially parallel to said horizontal axis, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said reflector axis and said condenser axis are substantially parallel to said horizontal axis and said condenser axis is raised by a predetermined distance D above said reflector axis, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       5. A projector headlamp according to claim  4 , wherein 0 mm<D≦5 mm. 
     
     
       6. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located substantially at said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a condenser axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield and said reflector between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and substantially parallel to said horizontal axis, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said reflector axis and said condenser axis are substantially parallel to said horizontal axis and said reflector axis is lowered by a predetermined distance E below said condenser axis, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       7. A projector headlamp according to claim  6 , wherein 0 mm<E≦5 mm. 
     
     
       8. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located substantially at said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a forward face and a condenser axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield and said condenser lens between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and substantially parallel to said horizontal axis, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said reflector axis is substantially parallel with said horizontal axis, and said forward face of said condenser lens is tilted upward such that said condenser axis is raised by an angle B with respect to said horizontal axis, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       9. A projector headlamp according to claim  8 , wherein 0°<B≦5°. 
     
     
       10. A projector headlamp according to claim  8 , wherein 1°≦B≦3°. 
     
     
       11. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located substantially at said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a condenser axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield and said reflector between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said reflector axis and said condenser axis are substantially collinear and substantially parallel to said horizontal axis, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said condenser axis is substantially parallel with said horizontal axis, and said reflector opening is tilted downward such that said reflector axis is lowered by an angle C with respect to said horizontal axis, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       12. A projector headlamp according to claim  11 , wherein 0°<C≦5°. 
     
     
       13. A projector headlamp according to claim  11 , wherein 1°<C≦3°. 
     
     
       14. A projector headlamp for projecting light in a forward direction generally along a horizontal axis selectably between high beam and low beam conditions, said projector headlamp comprising: 
       (a) a generally elliptical reflector having a reflector axis, first and second focal points located along said reflector axis, and a forward-facing reflector opening;  
       (b) a light source from which light waves may emanate, said light source being located generally proximate said first focal point;  
       (c) a light shield disposed generally beneath said second focal point and having a top edge;  
       (d) a condenser lens having a condenser axis substantially coaxial with said reflector axis, said condenser lens being disposed forward of said reflector opening and spaced apart from said second focal point effective to substantially collimate said light waves generally in said forward direction; and  
       (e) means for selectably moving said light shield and said light source between said low beam and high beam conditions;  
       (f) wherein in said low beam condition:  
       (i) said light source is positioned substantially coincident with said first focal point, and  
       (ii) said light shield is oriented in a first position wherein said top edge is positioned immediately beneath said second focal point; and  
       (g) wherein in said high beam condition:  
       (i) said light source is positioned above said first focal point by a predetermined distance F, and  
       (ii) said light shield is oriented in a second position wherein said top edge is lowered away from said second focal point.  
     
     
       15. A projector headlamp according to claim  14 , wherein 0mm<F≦5 mm.